Python distinguishes signed zeros by their repr:

# floats
>>> 0.0
0.0
>>> -0.0
-0.0

# complex
>>> complex(0.0, 0.0)  # A
0j
>>> complex(0.0, -0.0)  # B
-0j
>>> complex(-0.0, 0.0)  # C
(-0+0j)
>>> complex(-0.0, -0.0)  # D
(-0+0j)

However, only one of these `complex` reprs round-trips:

>>> 0j   # ok
0j
>>> -0j   # doesn't round-trip
(-0-0j)
>>> (-0+0j)  # doesn't round-trip
0j
>>> (-0-0j)
0j

This was reported and closed in https://bugs.python.org/issue17336, but it seems to me that this is easy to avoid - have `__repr__` return `complex(...)` for values which do not round-trip.

This is a known issue and I have a PR that does this that I could post but it was rejected when it was previously discussed: https://bugs.python.org/issue23229#msg233963

Closing here; to the extent that it's possible, let's keep the discussion in one place (comments can still be posted on closed issues). I'll add a comment on #17336.

Apologies for not searching the issue tracker effectively until after filing this.

[META] @Eric: No apology needed. I find the issue tracker search hard to use well, and in general we don't do a great job of tracking duplicates properly. I'm trying to be better about that.